The mission of the Biostatistics Core is to support and help promote high quality, innovative research in the COAST projects by providing the COAST IV investigators with access to quality data and sophisticated statistical design and analysis. In order to fulfill this mission, the Core staff will collaborate in the design, execution and analysis of the laboratory and clinical research studies and the development and application of new statistical methods as needed by the projects. Core staff will function as collaborative members of research teams. Core staff will be available for advice on statistical issues in the design, conduct, and analysis of studies related to the COAST IV projects. Advice may be related to a project-specific activity or internal review of general issues faced by an investigator. Core staff will also provide on-going support for the COAST IV projects. Core staff will interact with project investigators to identify research questions of interest and the relevant variables within the COAST I, II, III and IV databases. The Biostatistics Core has developed a sophisticated and secure Oracle database system for entering and storing COAST 1,11 and III study data. The Oracle system will continue to be used to manage data on the COAST cohort.